首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 687 毫秒
1.
High salt concentration in the soil is a serious problem in vast areas of otherwise productive agricultural lands in India. Establishment of salt tolerant vegetation could be an effective way of ameliorating this problem. In an 8-year field trial on an alkali soil, growth and biomass production ofProsopis juliflora was greater in sole stand than when interplanted with the grassLeptochloa fusca, but soil improvement was greater for the mixed tree-grass treatment.Prosopis accumulated substantially more biomass nutrients when in sole stand, but total nutrient recycling was similar with and without grass. Less salt tolerant but more palatable fodder crops such asTrifolium resupinatum, T. alexandrium andMelilotus denticulata were successfully grown withProsopis after removingL. fusca in theProsopis plus grass treatment 50 months after commencement. Tentative economic analysis suggests theProsopis plus grass system gives higher returns. TheProsopis-Leptochloa system combines production with biological reclamation, and is an appropriate form of reclamation agroforestry for alkali lands.  相似文献   

2.
The production of maize (Zea mays L.), guinea corn (Sorghum vulgare L.) and groundnuts (Arachis hypogea L.) grown in pots on soils sampled under neem (Azadiracta indica A. Juss), Eucalyptus camaldulensis Dehnh, and Prosopis juliflora Swartz, plantations in the Sahel region of Nigeria was investigated. Ordinary field soil adjacent to the plantation formed the control against which forest and species effects on the soil were compared.Crops, particularly maize and sorghum, produced higher dry matter on forest influenced soil than on ordinary field soil. The leguminous groundnuts however, appeared to have fixed its own nitrogen and therefore depended less on the inherent fertility advantages of the forest soil. The highest crop yield was obtained on the soil under neem followed by Prosopis, Eucalyptus and ordinary field. Since forest species differed in their effects on crop yield, further indentification, categorization and development of species with positive effects on crop yield was suggested for priority attention.  相似文献   

3.
Soil samples were taken at different distances from the trunks of four- to five-year-old trees of six species planted on-farm in western Kenya. The tree species wereCordia africana, Croton megalocarpoides, Grevillea robusta, Acacia tortilis, Prosopis juliflora andSesbania sesban. Samples were also taken inside and outside a fenced plantation ofProsopis juliflora. Soil samples were analysed for total C%, total N%,13C abundance,15N abundance, extractable P and pH.The most sensitive indicator of effects of trees on soils was13C abundance, which reflected a shift in inputs of C from C4 grasses to C from C3 trees. All species except Prosopis lowered the13C abundance by 0.5–1 -units. This was equivalent to an increase of 3–5% of the percentage of C contributed by C3 species. Prosopis trees did not decrease the13C abundance because of the abundant grass-growth around them. Cordia, which had the most pronounced effects, raised the C%, N% and extractable P by 27%, 26% and 55%, respectively. Nitrogen and C were well correlated (r 2=0.97) in the whole material. Effects on soil pH were in both directions, i.e. it was raised under the Prosopis plantation by 0.33 units, while it was lowered under Acacia by 0.21 units.Effects of agroforestry trees were thus seen in as short time as five years in practical onfarm situations.13C abundance is recommended as a particularly sensitive indicator of the influence of trees on sites previously dominated by C4 crops and grasses.  相似文献   

4.
A study was carried out to find suitable species and its combined surface vegetation with the aim of fast stabilization of dune and production of fuel and fodder from this highly stressed site. Seedlings of Acacia tortilis, Prosopis juliflora and Calligonum polygonoides species were planted on shifting dune and micro-windbreaks were erected to protect the seedlings from the drifting sand. Cassia angustifolia and Cenchrus ciliaris were sown as treatment (vegetation type) to develop undercanopy vegetation. Vegetation types had no significant (P>0.05) effect on the growth of the species. However, growth of species differed significantly (P<0.001) and P. juliflora was the best performer to cover soil in a best way. C. polygonoides produced the highest biomass in the form of fuelwood utilizing minimum amount of soil water. There was an increase in SOM and soil available NH4-N due to plantation and vegetation type treatments. C. polygonoides with C. ciliaris was the best combination for fuel and fodder production, whereas combination with C. angustifolia was the best to control sand drift. Sowing of undershrubs and grass of local importance can also be done in advance to control the sand drift and burial of the planted seedlings. It will help in the improvement of soil conditions and control the sand drift when the seedlings attain greater height leaving bare the undercanopy soil.  相似文献   

5.
A green house pot trial was conducted to assess the impact of Prosopis afforestation on the productivity and fertility of degraded sodic soils in Haryana, India. Wheat (Triticum aestivum, L; cultivar HD 2329) plants were grown from seed on top soils collected from a chronosequence of 0, 5, 7, and 30-year-old Prosopis juliflora plantations established on highly sodic soils and a non-sodic reference soil collected from a local farm. The afforestation improved physical and chemical properties of surface soils by decreasing pH, electrical conductivity and exchangeable Na levels, and increasing infiltration capacity, organic C, total N, available P, and exchangeable Ca, Mg, and, K levels. The amelioration effect of the trees on top soil increased with duration of tree occupancy. Soil nutrient status under the 30-year-old plantation was higher than that of the non-sodic farm soil. The reduced soil sodicity and improved fertility contributed to higher germination, survival, growth, and grain yield of wheat plants grown on the Prosopis chronosequence soils, even surpassing the yield attained on the farm soil in the case of 30-year-old plantation soil. Sodium accumulation in the crop declined while N, P, K, Ca, and Mg uptake increased with soil plantation age reflecting the changing nutrient status of the rooting zone due to afforestation. Results confirmed that successful tree plantation may restore the productivity and fertility of highly degraded sodic soils.  相似文献   

6.
There is little available information on nutrient cycling and the controls of ecosystem processes in land use systems of dry neotropical regions. In this study, we conducted field and glasshouse experiments to investigate the influence of Ziziphus joazeiro and Prosopis juliflora trees on microclimate and nutrient dynamics in pastures ofCenchrus ciliaris in semiarid northeastern Brazil. We found that soil moisture was lower under the crowns of P. juliflora trees during early season in comparison to patches ofC. ciliaris (grass patches), but the presence of Z. joazeiro had no effect on soil moisture. Soil and air temperatures were lower under Z. joazeiro in comparison to grass patches but P. juliflora had little effect on temperature. Losses of P from all litter types were lower under the crowns of Z. joazeiro trees, but losses of biomass and N from litter were not consistently affected by the presence of trees. Soil net N mineralized was greater under both tree species, in comparison to grass patches. However, net soil N mineralized per gram of total soil N was greater under the crowns of the potentially N2 fixing P. juliflora, in comparison to grass patches, while there were no significant differences betweenZ. joazeiro crowns and grass patches. In the glasshouse study, plant biomass and nutrient uptake was greater in soil collected under the crowns of both tree species, in comparison to soil from grass patches. Our results indicate that the preservation of native trees or introduction of exotic tree species in C. ciliaris pastures in semiarid northeastern Brazil significantly affects microclimate and the dynamics of litter and soil nutrients, and may contribute to increases in the cycling rate of nutrients in these systems. Index terms: buffel grass, caatinga, nitrogen mineralization, Prosopis juliflora, Ziziphus joazeiro.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

7.
In sodic soils, excessive amounts of salts have an adverse effect on soil biological activity and stability of soil organic matter. The study analyzes the role of silvopastoral systems to improve soil organic matter and microbial activity with a view for effective management of soil fertility. The silvopastoral systems for the present study (located at Saraswati Reserved Forest, Kurukshetra; 29°4′ to 30°15′ N and 75°15′ to 77°16prime; E) are characterized by tree species of Acacia nilotica, Dalbergia sissoo and Prosopis juliflora along with grass species of Desmostachya bipinnata and Sporobolus marginatus. Soil microbial biomass carbon was measured using the fumigation extraction technique and nitrogen mineralization rates using aerobic incubation method. The microbial biomass carbon in the soils of D. bipinnata and S. marginatus treatments were low. In silvopastoral systems, microbial biomass carbon increased due to increase in the carbon content in the soil – plant system. A significant relationship was found between microbial biomass carbon and plant biomass carbon (r = 0.83) as well as the flux of carbon in net primary productivity (r = 0.92). Nitrogen mineralization rates were found greater in silvopastoral systems compared to 'grass-only' system. Soil organic matter was linearly related to microbial biomass carbon, soil N and nitrogen mineralization rates (r = 0.95 to 0.98, p < 0.01). On the basis of improvement in soil organic matter, enlarged soil microbial biomass pool and greater soil N availability in the tree + grass systems, agroforestry could be adopted for improving the fertility of highly sodic soil. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

8.
Land use influences physico-chemical and water transmission properties of soil, which ultimately determine the suitability of land for different purposes. In present study, impact of different land use (forest and agriculture) on selected physicochemical and hydrological properties of soil was evaluated and compared with a reference site (uncultivated ravinous wasteland). Land use influenced infiltration rate, bulk density, mean weight diameter of aggregates and plant available water of soils. After 25 years of plantation of forest species, soil organic carbon content increased by more than twofold and mean weight diameter of aggregates by 2- to 6-fold in comparison to reference site. Significant reduction in soil bulk density (4–18%) and increase in steady state infiltration rate (1.5–2 times) was observed under the forest land use system. Conversion of ravine to forest system resulted in significant improvement in moisture retention capacity of soil. Conversion of ravine landform to agriculture adversely affected the soil bulk density and infiltration rate. The study provided practical information regarding rehabilitation potential of different tree species (Prosopis juliflora, Leucaena leucocephala, Acacia nilotica and Azadirachta indica) that could be used for restoration of ustifluvent soil susceptible to gully erosion in the semi-arid region.  相似文献   

9.
A pot experiment in Kenya examined the effects of mycorrhizal and rhizobial inoculation on the growth and symbiont infection of Acacia tortilis seedlings in unsterile soil, in comparison with sterile and unsterile soil controls. Three mixed, arbuscular mycorrhizal inocula, originating from A. tortilis, Terminalia brownii, T. spinosa and Prosopis juliflora (produced under nursery conditions), were used to inoculate the seedlings, which also received a standard, mixed, rhizobial inoculum. Mycorrhizal infection and plant growth were significantly affected by experimental treatment (p<0.001). Some mycorrhizal infection (presumably with indigenous soil-borne inoculum) occurred in the unsterile soil control, but not in the sterile soil control, indicating that transfer of inoculum between pots in the experiment did not occur. Mycorrhizal formation was significantly more extensive in inoculated plants, which also had better shoot and root growth. 24 weeks after inoculation, plants which had received inoculum of A. tortilis origin were 105 mm tall and their roots were 56% mycorrhizal, whereas the controls most representative of normal nursery treatment were only 77 mm tall and 29% mycorrhizal. Nodulation was erratic and poor in all treatments. The results suggest that mycorrhizal inoculation can improve both mycorrhizal infection and growth of tree seedlings in unsterile nursery soil. The methods of culture and inoculation described here could easily be adopted by nurseries at little cost.  相似文献   

10.
Growth responses of mesquite (Prosopis juliflora (SW) DC.) during establishment stage to planting methods and amendments were studied in a highly alkali soil (Aquic Natrustalf, ESP 94), at the experimental farm of the Central Soil Salinity Research Institute, Karnal in July, 1984. Six combinations of planting methods and amendments with and without Karnal grass (Diplachne fusca Linn. P Beauv) in the inter-row space were compared in a four times replicated field experiment in randomised block design. The mean plant height (MPH), diameter at stump height (DSH), diameter at breast height (DBH), lopped biomass 16 months past planting and total biomass attained in 2 years period were significantly less when inter-row space was planted with Karnal grass. The MPH (cm), DSH and DBH (mm) attained in 2 years period were 319, 43.4 and 15.1 in with grass as compared to 405, 53.4 and 20.3 in without grass treatments. Similarly, the total biomass attained in 2 years was about 3 times more where inter-row space was not planted with grass. Growth was better when mesquite was planted by auger hole and pit methods than in trench plantation, when the original soil was treated with gypsum at 3 kg plant–1 and then refilled. However, using trenches of dimensions 30 × 30 cm and filled with a mixture of original soil, 3 kg gypsum and 8 kg farm yard manure plant–1 appeared to be promising method for establishing mesquite plantations on highly deteriorated alkali soils. The effect of amendments on growth decreased in the order gypsum + FYM, gypsum + rice husk, gypsum, control. In two years period, 37 percent mesquite died in the trenches in which the original soil was left unchanged. Effect of treatments on nutrient concentrations and total accumulations in different segments of mesquite is discussed. Karnal grass gave 25.3 t ha–1 green forage yield in 8 cuts without amendment in a growth period of 26 months proving its great potential as a folder crop for the adverse sites. The inorganic chemical composition of the shoots, including trace elements Fe, Mn, Zn and Cu, is such as to make this species a highly promising plant for the exploitation of alkali soils. Growing Karnal grass with mesquite for a period of about 2 years reduced soil pH and EC significantly and improved organic carbon and available N contents. The grass improved water infiltration rates and moisture storage in the lower layers of the profile.  相似文献   

11.
Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica (L.) Willd. ex Del., Prosopis juliflora (Sw.) DC. and Dodonaea viscosa (L.) Jacq. The following treatments were applied: T1, untreated seed (control); T2, sulphuric acid (97%) for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog (MS) medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds (80.8%-90.8%) and for scarified seeds of A. nilotica (50.2%) boiled in water. The germination indices, i.e., final germination percentage (FG), mean daily germination (MDG) and germination rate (GR), were significantly affected by treatments and species (p<0.01).  相似文献   

12.
Growth performances of some multipurpose trees and shrubs have been studied for five years at two locations in the semi-arid areas of Southern Ethiopia. The best performance in terms of rates of survival and growth rates (height and diameter growth) has been attained byAcacia nilotica, A. Cyanophylla, A. seyal, Cassia siamea andProsopis juliflora. Given the ecological limitations of semi-arid areas, growth rates of these species is promising and this indicates that sustainable production system can be realized using proper agroforestry technologies in the semi-arid areas of Southern Ethiopia and similar area types elsewhere.  相似文献   

13.
Tree-based land-use systems could sequester carbon in soil and vegetation and improve nutrient cycling within the systems. The present investigation was aimed at analyzing the role of tree and grass species on biomass productivity, carbon sequestration and nitrogen cycling in silvopastoral systems in a highly sodic soil. The silvopastoral systems (located at Saraswati Reserved Forest, Kurukshetra, 29°4prime; to 30°15prime; N and 75°15prime; to 77°16prime; E) consisted of about six-year-old-tree species of Acacia nilotica, Dalbergia sissoo and Prosopis juliflora in the mainplots of a split-plot experiment with two species of grasses, Desmostachya bipinnata and Sporobolus marginatus, in the subplots. The total carbon storage in the trees + grass systems was 1.18 to 18.55 Mg C ha−1 and carbon input in net primary production varied between 0.98 to 6.50 Mg C ha−1 yr−1. Carbon flux in net primary productivity increased significantly due to integration of Prosopis and Dalbergia with grasses. Compared to 'grass-only' systems, soil organic matter, biological productivity and carbon storage were greater in the silvopastoral systems. Of the total nitrogen uptake by the plants, 4 to 21 per cent was retained in the perennial tree components. Nitrogen cycling in the soil-plant system was found to be efficient. Thus, It is suggested that the silvopastoral systems, integrating trees and grasses hold promise as a strategy for improving highly sodic soils. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

14.
The present study was conducted to evaluate the effect of different concentrations of salts on seed germination and seedling growth of Prosopis juliflora. The experiment was carried out in Forestry Laboratory at Sari Agricultural Sciences and Natural Resources University, Iran. The collected seeds were treated with boiling water and H2SO4 then left to germinate in controlled growth chamber. Seed were grown under salinity levels 100, 200 and 300 mM of CaCl2, NaH2PO4, KNO3 and KH2PO4. Germination parameters and various seedling growth variables such as root and stem length, seedlings fresh and dry weight were measured after 56 days. Results showed that germination percentage significantly decreased as the salinity level of medium increased. Salinity treatments at 100 mM enhanced the percentage of seeds germination and significantly improved the germination index and seeds stamina. In this study, the best treatment was 100 mM salinity for biomass production of seedlings. For Prosopis juliflora, 100 mM salinity significantly enhanced both germination and biomass production.  相似文献   

15.
The nitrogen fixing trees of the Prosopis juliflora/P. pallida complex are among the most adaptable and fastest growing trees in the truly tropical arid regions and have become naturalized in semi-arid tropics in Latin America, the Caribbean, Hawaii, Sahelian Africa, the Indian subcontinent and northern Australia. The trees have been regarded both as a serious weed and as a valuable resource for firewood and dune stabilization. Unfortunately the introductions into Sahelian Africa and the Indian subcontinent were from trees that had non-palatable pods. Despite their widespread occurrence, seed from a genetic improvement program is not available. Peruvian Prosopis has rapid growth, erect form and high survival of in Haiti, Cape Verde and India. An evaluation of form, diameter at breast height, pod production and pod palatability was conducted in a 10 year old plantation of 1,800 trees in Piura, Peru and seven were selected that had: more than 20 cm DBH; an erect form; 100% of branches with pods; and pods with a very sweet flavor. Scions and budwood were taken from these trees and successively grafted onto greenhouse grown stock plants to be used for clonal multiplication. For the first time we report successful chip budding grafting of Prosopis. This is the first report of Peruvian clones that have been selected for high production of highly palatable sweet pods. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

16.
Multipurpose trees and shrubs on farmlands in Tamil Nadu State (India)   总被引：1，自引：0，他引：1  
Farmers in Tamil Nadu State integrate numerous species of multipurpose trees and shrubs on their farmlands in close association with agricultural crops and/or livestock. The dominant among them areBorassus flabellifer, Tamarindus indica, Ceiba pentandra, Acacia leucophloea andA. nilotica.These woody perennials are better able to cope with poor growing conditions. Their increasing integration on farmlands represents a strategy to minimise risk of crop failure. Some species (e.g.Prosopis juliflora andDelonix elata) are deliberately used to ameliorate infertile or saline soils in order to permit the growing of annual crops. In addition to producing fuelwood, charcoal, fruit and fodder and providing many service functions, these species require only fewer inputs and give the farmer a choice of management options in the event of poor crop growth. The productivity of these traditionally managed and little-studied agroforestry systems can considerably be improved by scientific interventions.  相似文献   

17.
徐德应  聂道平 《林业科学》1994,30(4):358-363
为了探索我国南方亚热带地区竹林下放牧的可行性，我们设计了一种“竹—牛—草”复合生态系统，进行竹林下养牛试验。通过试验、调查和测定，构成一个比较完整的数学模型。利用系统动力学对这一系统进行定量分析。模型考虑了毛竹的产量及其经济收益、养牛所需的成本和收益等经济因素，还考虑到牛的践踏对于土壤物理性质的影响及对草被生长的影响，草被的载畜能力及其它反馈机制。这一综合性的系统动力学模型，主要用于评估在何种条件下这一系统具有高经济效益。模型还设定了七种选择方案，每种方案都以竹子的砍伐年龄为标准，试图对竹林下放牧的长期生态后果进行评估。得出的结论是：通过林下放牧或舍饲养牛并不能有效地改善竹林区的经济现状，但如果技术条件足够并有广大的销售市场，采用舍饲方式饲养生长迅速的肉牛或以售牛奶为其经营方针，则经济效益有可能大幅度提高。  相似文献   

18.
Trees of the genus Ficus, integral components of indigenous rainfed agro-ecosystems of the southern dry agro-climatic zone of Karnataka, southern India, have traditionally been associated with the ecological service of soil quality enhancement in addition to various direct use benefits. We assessed the soil enrichment service of Ficus benghalensis L. a common Ficus species in these agroforestry systems, by quantifying nutrient return via litter fall. Litterfall estimation and chemical analysis of litter showed that F. benghalensis trees produce 3,512 kg ha-1 of litter annually which, on decomposition, can satisfy up to 76.70 % of N, 20.24% of P and 67.76% of K requirements of dryland crops annually per hectare. This can lead to an avoided cost of compost of US $ 36.46 ha-1·a-1 in dryland farming systems. The slow rate of decay of Ficus litter, as revealed in litter decomposition studies indicates its potential as ideal mulch for dryland soils. We discuss the complementarity between Ficus litterfall and cropping patterns in Mandya, and its implications for rainfed agricultural systems.  相似文献   

19.
For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L−1 and 500 mg·L−1 and combinational treatment of scarification with gibberellic acid of 250 mg·L−1 and 500 mg·L−1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.  相似文献   

20.
Soil microbes may be critical players in determining the allelopathic potential of some plants. Low levels of plant community biodiversity in Eucalyptus plantations have been attributed to the allelopathic potential of these tree species. The role of soil microbes in the allelopathic effect of leaf leachates of the hybrid tree Eucalyptus grandis × E. urophylla, was tested in Petri dish assays with Brassica chinensis as a receiver plant. Soils were collected from either a local garden (soil A) or a Eucalyptus plantation (soil B) and half of each soil was sterilized to remove microbes. These soils were then treated with E. grandis × E. urophylla leachates for 0–72 h. Seed germination of B. chinensis was significantly inhibited in soils treated with leaf leachates relative to untreated soils. The inhibitory effect of the leaf leachates was more pronounced in sterilized soils. Total phenolic content was obvious lower in nonsterile leachate-treated soils than in sterile soils. Biomass of B. chinensis was negatively correlated with the total phenolic content in soils. Our findings suggest that soil microbes can alleviate the allelopathic potential of Eucalyptus and thereby its negative impact on plant growth.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号